Hair fastener



FIG. 1 is a top front perspective view of the hair fastener showing my new design;

FIG. 2 is a top plan view;

FIG. 3 is a bottom plan view; the broken lines in the drawing are for illustrative purposes only and form no part of the claimed design;

FIG. 4 is a front elevation view;

FIG. 5 is a rear elevation view, with the front and rear being identical;

FIG. 6 is an elevation view of the left side; and,

FIG. 7 is an elevation view of the right side, with the left side and right side being identical. 

The ornamental design for a hair fastener, as shown and described. 